JP2010125619A - Liquid drop ejector and liquid drop ejection head unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To hardly cause pressure fluctuation in a circulating line in a head having ink circulation effective in preventing thickening of ink. <P>SOLUTION: Ink circulating between a recording head 18 and an ink tank 20 circulates within a recording head unit 15 without passing through the outside of the recording head unit 15. The circulating line 80 does not thereby become long-sized. Consequently, pressure fluctuation in the circulating line 80 is hardly caused in comparison with constitution of the circulating line 80 distributed to the outside of the recording head unit 15 to become long-sized. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge device and a droplet discharge head unit.

  As a droplet discharge device, an inkjet recording device disclosed in Patent Literature 1 and Patent Literature 2 is known.

  A recording apparatus 10 disclosed in Patent Document 1 includes an ejection head 12 and an ink circulation system 20. The ink circulation system 20 includes a main tank 14, a supply sub tank 16 that supplies ink to the ejection head in a static pressure manner, a replenisher tank 22, and a communication pipe 50. A path through which ink in the ink circulation system 20 circulates is formed so as to be sealed from the atmosphere. At least a part of the ink circulation system 20 is provided with a pressure adjusting body for adjusting the internal pressure of the ink circulation system. The pressure adjusting body is formed using a soft material exhibiting flexibility. Ink circulation can prevent an increase in viscosity and nozzle clogging due to ink drying by forming a gentle ink flow in the head.

In the recording apparatus disclosed in Patent Document 2, when the liquid level sensor detects that the ink level in the second ink chamber 32 of the ink tank 20 has fallen below a predetermined position, the pipe 56 of the ports 50 and 52 is used. Is inserted into the slit valves 44 and 46 of the second ink chamber 32. Here, by driving the pump 86, the air in the second ink chamber 32 is sucked and discharged, the negative pressure in the second ink chamber 32 is increased, and ink is supplied from the main tank 24 to the second ink chamber 32. As described above, since the ink is supplied by the negative pressure, it is possible to prevent the ink leakage from the portion where the pipe 56 is inserted into the slit valve 46.
Japanese Patent Laid-Open No. 2006-15640 (FIG. 1) JP 2001-138541 A (FIG. 1)

  An object of the present invention is to make it difficult for pressure fluctuations in the circulation path to occur.

  According to a first aspect of the present invention, there is provided a liquid droplet ejection apparatus according to a first aspect of the present invention, a movable body, a liquid droplet ejection head that is provided on the movable body and ejects liquid droplets while moving integrally with the movable body, Provided in the movable body, and the liquid is circulated between the droplet discharge head and the liquid storage unit, and receives an external force. And at least a part of which can be deformed, and a circulation path in which a circulation flow is generated by the deformation.

  According to a second aspect of the present invention, there is provided the droplet discharge device according to the first aspect, wherein the droplet discharge device is configured separately from the moving body, and an external force is applied to the circulation path so that the liquid circulates. An external force applying means for deforming at least a part of the road is provided.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the circulation path is formed of a film body in which at least a part of the outer wall is exposed to the outside of the moving body,
The external force applying means is a cam whose outer periphery is pressed against the film body.

  A droplet discharge head unit according to a fourth aspect of the present invention is provided in a movable body, and is provided in the movable body, the droplet discharge head that discharges droplets while moving integrally with the movable body, and the liquid A liquid storage section that stores liquid supplied to the droplet discharge head; and a liquid that is circulated between the liquid droplet discharge head and the liquid storage section provided at the moving body, and receives at least a part of the external force. And a circulation path in which a circulation flow is generated by the deformation.

  According to the configuration of the first aspect of the present invention, pressure fluctuations in the circulation path are less likely to occur than in a configuration in which the circulation path is extended outside the movable body.

  According to the structure of Claim 2 of this invention, compared with the structure by which an external force provision means is provided in a moving body, size reduction of a moving body can be achieved.

  According to the structure of Claim 3 of this invention, compared with the case where this structure is not provided, a circulating flow can be produced effectively.

  According to the configuration of claim 4 of the present invention, pressure fluctuations in the circulation path are less likely to occur than in a configuration in which the circulation path is extended to the outside of the moving body.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

  In this embodiment, as an example of a droplet discharge device that discharges droplets, an ink jet recording device that discharges ink droplets and records an image on a recording medium will be described.

  The droplet discharge device is not limited to the ink jet recording device. As a droplet discharge device, for example, a color filter manufacturing device that manufactures a color filter by discharging ink or the like onto a film or glass, a device that forms a bump for mounting components by discharging molten solder onto a substrate Further, an apparatus for forming a wiring pattern by discharging a liquid containing a metal and various film forming apparatuses for forming a film by discharging a droplet may be used as long as the apparatus discharges a droplet.

(Configuration of inkjet recording apparatus according to this embodiment)
First, the configuration of the ink jet recording apparatus according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an ink jet recording apparatus according to the present embodiment.

  As shown in FIG. 1, an ink jet recording apparatus 10 according to this embodiment includes a transport roll 12 as an example of a transport unit that transports a recording medium P such as paper.

  The ink jet recording apparatus 10 includes a recording medium storage unit (not shown) that stores a recording medium P on which an image is recorded, and a recording medium discharge unit (not shown) that discharges the recording medium P on which an image is recorded. And. The recording medium P accommodated in the recording medium accommodation unit is conveyed by the conveyance roll 12 toward the recording medium discharge unit.

  Furthermore, the inkjet recording apparatus 10 moves in the main scanning direction (arrow B direction) that intersects the transport direction (sub-scanning direction, arrow A direction) in which the transport roll 12 transports the recording medium P as an example of a moving moving body. A carriage 16 is provided. The carriage 16 is reciprocated along the main scanning direction by a moving mechanism 13 that moves the carriage 16.

  The carriage 16 is provided with a recording head unit 15 as an example of a droplet discharge head unit. The recording head unit 15, as an example of a droplet discharge head that discharges droplets while moving integrally with the moving body, moves integrally with the carriage 16 toward the recording medium P transported by the transport roll 12. A plurality of recording heads 18 for discharging ink droplets are provided. The plurality of recording heads 18 are configured to eject black, yellow, magenta, and cyan inks.

  In the ink jet recording apparatus 10, the recording head 18 is selectively ejected from the recording head 18 to the recording medium P while moving in the main scanning direction integrally with the carriage 16 by the moving mechanism 13. One line in the main scanning direction in the image is recorded.

  When one movement in the main scanning direction is completed, the recording medium P is conveyed in the sub-scanning direction by the conveying roll 12, and the recording head 18 moves again in the main scanning direction (the opposite direction to the above). The next line in the main scanning direction in the image based on the image data is recorded. By repeating such an operation a plurality of times, the entire image based on the image data is recorded in full color on the recording medium P.

  The recording head unit 15 includes a plurality of ink tanks 20 that store ink supplied to each recording head 18 as an example of a liquid storage unit that stores liquid supplied to the droplet discharge head. The ink tank 20 stores ink of colors corresponding to the respective colors of the recording head 18.

  The ink tank 20 is disposed above the recording head unit 15, the recording head 18 is disposed above the recording head unit 15, and the ink tank 20 is located above the recording head 18.

  Each ink tank 20 and each recording head 18 are integrated for each color, and are configured as a recording head unit 15 that is a unit that can be replaced integrally. The recording head unit 15 is detachably provided on the carriage 16 and is replaced when the recording head 18 reaches the end of its life. In a new head unit, ink is filled in the ink tank 20 and the recording head 18 in advance.

  FIG. 1 illustrates two recording head units 15 among the four recording head units 15.

  The casing 21 of the recording head unit 15 is made of, for example, polypropylene that can sufficiently suppress moisture permeability and gas permeability. The housing 21 may be made of other materials.

  Further, the recording head unit 15 can be stopped at a stop position (home position) at an end portion in the main scanning direction of the ink jet recording apparatus 10. Specifically, the stop position is a position that is out of the image recording area where the image can be recorded on the recording medium P, and is a standby position for waiting when the recording head 18 is not recording.

  At the end of the ink jet recording apparatus 10 in the main scanning direction, a circulation unit 55 for circulating ink between the recording head 18 and the ink tank 20 and a replenishment station 22 for replenishing ink to the ink tank 20 are provided. Is provided. The circulation unit 55 and the replenishment station 22 are arranged to face each other so as to sandwich the recording head unit 15 located at the stop position.

  Further, a cap 23 that covers the nozzle 36 of the recording head 18 is provided at an end portion in the main scanning direction of the inkjet recording apparatus 10 so as to face the nozzle 36 of the recording head 18 of the recording head unit 15 that is located at the stop position. (See FIG. 2). A suction device (not shown) for sucking ink from the nozzles 36 is connected to the cap 23. A main tank 24 that stores ink supplied to the ink tank 20 by the replenishment station 22 is disposed below the ink jet recording apparatus 10.

  By the replenishment station 22, the circulation unit 55, the cap 23, and the suction device, various recovery operations and maintenance operations are performed on the recording head 18 located at the stop position. The maintenance operation including ink circulation is not limited to this stop position, and may be performed at another position.

  As various recovery operations / maintenance operations, for example, the cap 23 covers the nozzles 36 of the recording head 18 to suppress an increase in ink viscosity due to drying. For example, the cap 23 forms a sealed space by covering the nozzle 36, and the ink is sucked from the nozzle 36 of the recording head 18 by the suction device connected to the cap 23 in this state. The configurations of the replenishment station 22 and the circulation unit 55 will be described later.

  As shown in FIG. 2, the recording head 18 includes a nozzle 36 that ejects droplets, a head liquid chamber 34 that temporarily stores ink filled in the nozzle 36, and the ink supplied from the ink tank 20. And a filter 39 for preventing dust, coarse particles, and the like contained in the recording head 18 from entering the recording head 18.

  The head liquid chamber 34 has an outer shape that is, for example, a triangle surrounded by a bottom side and two oblique sides in a side view. In the head liquid chamber 34, an ink inlet 34A is formed on one of the oblique sides on the upper side of the head liquid chamber 34, and an outlet 34B is formed on the other side.

  A supply path 38 for supplying ink from the ink tank 20 is connected to an inlet 34A of the head liquid chamber 34, and communicates with the head liquid chamber 34 at the inlet 34A. The filter 39 is disposed at the inlet 34 </ b> A of the head liquid chamber 34. The filter 39 is also disposed on the outlet 34B side of the head liquid chamber 34.

  As a result, the ink supplied from the ink tank 20 to the recording head 18 passes through the filter 39, and the ink flows into the head liquid chamber 34 from the inlet 34 </ b> A of the head liquid chamber 34.

  The nozzle 36 and the head liquid chamber 34 communicate with each other through a nozzle side flow path 37, and the ink supplied to the head liquid chamber 34 is supplied to the nozzle 36 through the nozzle side flow path 37. When ink is consumed by ejecting ink from the nozzle 36, ink is filled from the head liquid chamber 34 into the nozzle 36 by the capillary force of the nozzle 36.

  As shown in FIG. 2, the ink tank 20 includes a first ink chamber 30 in which a porous body 26 impregnated with ink is accommodated, and a second ink chamber 32 in which ink is stored. The ink tank 20 may be configured to include either the first ink chamber 30 or the second ink chamber 32.

  The first ink chamber 30 and the second ink chamber 32 are partitioned by a partition wall 33 and are configured as separate chambers. A slit (gap) 35 is formed in the partition wall 33 that partitions the first ink chamber 30 and the second ink chamber 32, and the first ink chamber 30 and the second ink chamber 32 communicate with each other through the slit 35. .

  Further, the first ink chamber 30 is formed with an atmosphere opening port 28 that is open to the atmosphere, and the first ink chamber 30 is open to the atmosphere. The second ink chamber 32 is a sealed space.

  The porous body 26 of the first ink chamber 30 is formed with a large number of micropores and holds ink in these micropores. The porous body 26 generates a negative pressure by a capillary force due to the micropores.

  Further, as the porous body 26 accommodated in the first ink chamber 30, for example, polyester felt is used. Polyester felt is suitable because it can adjust the capillary force by changing the density and has excellent ink resistance. Of course, a porous polymer foam (polyurethane, melamine) or the like, or a felt other than polyester fiber, such as polypropylene or acrylic, may be used as long as an appropriate capillary force is exerted between the ink and the ink.

  When ink is consumed by the recording head 18, the ink flows from the second ink chamber 32 into the head liquid chamber 34 of the recording head 18. When the ink in the second ink chamber 32 decreases, the pressure in the second ink chamber 32 becomes negative, and the ink impregnated in the porous body 26 flows from the first ink chamber 30 into the second ink chamber 32. When the ink flows into the second ink chamber 32, the pressure difference between the second ink chamber 32 and the first ink chamber 30 is eliminated, and the pressure between the second ink chamber 32 and the first ink chamber 30 is balanced. Incidentally, the supply of ink to the second ink chamber 32 is stopped.

  When ink is supplied from the porous body 26 to the second ink chamber 32 and the ink impregnated in the porous body 26 is depleted, air passes through the slit 35 to the porous body 26 of the first ink chamber 30. To reach.

  Further, the negative pressure (back pressure) due to the capillary force of the porous body 26 acts on the ink in the recording head 18 through the ink in the second ink chamber 32. Thereby, ink leakage from the nozzles 36 of the recording head 18 is suppressed, and the shape of the ink meniscus (the liquid level in the nozzles 36) is maintained well.

  The second ink chamber 32 is provided with a detection sensor 41 for detecting the remaining amount of ink in the second ink chamber 32. The detection sensor 41 includes, for example, optical liquid level sensors 40 and 42 provided with a prism.

  The optical liquid level sensors 40 and 42 perform liquid level detection by irradiating light from the light emitting diode to the prism disposed on the side surface of the second ink chamber 32 and causing the reflected light to enter the phototransistor. Yes.

  That is, when ink is present on the reflecting surface of the prism, incident light is transmitted through the ink tank and is not reflected. On the other hand, when there is no ink on the reflecting surface of the prism, the reflecting surface is designed to totally reflect the incident light, and the ink liquid level is lower than that of the prism when the reflected light enters the phototransistor. Detecting that

  The optical liquid level sensor 40 is disposed above the optical liquid level sensor 42 on the side surface of the second ink chamber 32, and is used to detect the upper limit of the ink liquid level when refilling ink, which will be described later. The optical liquid level sensor 42 is disposed below the optical liquid level sensor 40 on the side surface of the second ink chamber 32, and detects that the remaining amount of ink has decreased to an ink liquid level that requires ink replenishment. Used to do.

  The detection sensor 41 for detecting the remaining amount of ink in the second ink chamber 32 is not limited to an optical liquid level sensor, and various sensors can be used.

  Next, an ink replenishment system for replenishing ink to the second ink chamber 32 will be described.

  On the side surface of the second ink chamber 32, slit valves 44 and 46 to which ports 50 and 52 to be described later can be connected are provided. The slit valves 44 and 46 have a slit structure using an elastic member such as rubber, and when the pipe 56 of the replenishment station 22 to be described later is inserted, the slit valves 44 and 46 open while closely sealing to the outer peripheral surface of the pipe 56. . Except when the pipe 56 is inserted, the slits of the slit valves 44 and 46 are closed, the second ink chamber 32 is airtight, and the negative pressure in the second ink chamber 32 is controlled within a certain range.

  The slit valve 44 is disposed above the optical liquid level sensor 40. This is because the air is discharged from the port 50 inserted into the slit valve 44, so that the port 50 is inserted above the upper limit of the ink liquid level.

  The slit valve 46 is disposed below the optical liquid level sensor 42, and the port 50 is inserted below the lower limit of the ink liquid level. This is because ink is supplied into the ink from the port 52 inserted into the slit valve 46.

  The replenishment station 22 has two ports 50 and 52 connected to the second ink chamber 32. As shown in FIG. 2, the port 50 includes a base 54, a pipe 56 passing through the base 54, a spring 58 wound around the pipe 56, and a support movable along the pipe 56. A member 60 and a protective cover 62 supported by the support member 60 are provided.

  The pipe 56 has a passage (not shown) formed therein, and communicates with the outside through an opening 64 formed near the tip. The tip of the pipe 56 is shielded from the outside by a conical seal portion 66 provided at the tip of the protective cover 62 so that ink does not evaporate or denature in the opening 64.

  The spring 58 is disposed between the base 54 and the support member 60, and the spring 58 is caused by a force acting on the support member 60 toward the base 54 (the base end side of the port, in the direction of arrow C). The support member 60 and the protective cover 62 move in the C direction and the pipe 56 is exposed to the outside.

  The pipe 56 of the port 50 is connected to an exhaust pipe 84 that is opened to the atmosphere, and an exhaust pump 86 is disposed in the exhaust pipe 84.

  The port 52 has the same configuration as the port 50, and the pipe 56 is connected to a supply port 70 formed at the bottom of the main tank 24 via a supply pipe 72. The main tank 24 has an air opening that is open to the atmosphere, and the main tank 24 is open to the atmosphere.

  The replenishment station 22 is configured to be close to and away from the side surface of the second ink chamber 32 by the actuator 90 (in the directions of arrows D and C). When the replenishment station 22 is brought close to the side surface of the second ink chamber 32, the protective cover 62 hits the side surface and the spring 58 is compressed.

  As a result, the pipe 56 is exposed from the protective cover 62 and the tip (opening 64) is inserted into the second ink chamber 32 through the slit valves 44 and 46 (see FIG. 3). At this time, the pipe 56 of the port 50 is inserted into the air of the second ink chamber 32, and the pipe 56 of the port 52 is inserted into the ink of the second ink chamber 32.

  In this state, when the driving of the actuator 90 is stopped and the pump 86 is driven, the air in the second ink chamber 32 is discharged to the outside through the exhaust pipe 84. Accordingly, the negative pressure in the second ink chamber 32 increases, and ink is supplied from the main tank 24 to the second ink chamber 32 through the supply pipe 72, the pipe 56, and the opening 64.

  Thus, in the ink jet recording apparatus 10 of this embodiment, in order to replenish ink from the main tank 24 to the ink tank 20, the ports 50 and 52 are connected to the second ink chamber 32 of the ink tank 20, and the pump 86 is connected. The ink is sucked from the main tank 24 into the second ink chamber 32 by discharging the air in the second ink chamber 32 from the port 50 and increasing the negative pressure in the second ink chamber 32. That is, since ink is supplied by negative pressure, it is difficult for ink to leak from the slit valve 46 in which the pipe 56 of the port 52 is inserted.

  When the pipes 56 of the ports 50 and 52 are inserted into the slit valves 44 and 46, the atmosphere opening port 28 of the first ink chamber 30 is closed by the cap portion 59, and the nozzle 36 of the recording head 18 is Capped by cap 23.

  This suppresses air from entering from the atmosphere opening port 28 and the nozzle 36 of the recording head 18 as the negative pressure of the second ink chamber 32 is increased by driving the pump 86.

(Configuration for circulating ink between the recording head 18 and the ink tank 20)
Next, a configuration for circulating ink between the recording head 18 and the ink tank 20 will be described.

  As shown in FIGS. 2, 3, and 4, the recording head unit 15 is provided with a supply path 38 for supplying ink from the second ink chamber 32 to the head liquid chamber 34. The supply path 38 has a start end (one end) connected to the lower portion of the second ink chamber 32 and a terminal end (the other end) connected to the inlet 34A of the head liquid chamber 34 in which the filter 39 is disposed. ing. The ink in the second ink chamber 32 flows through the supply path 38, passes through the filter 39, and flows into the head liquid chamber 34.

  In addition, a return path 45 for returning ink from the head liquid chamber 34 to the second ink chamber 32 is formed in the recording head unit 15. The return path 45 has a start end (one end) connected to the outlet 34B of the head liquid chamber 34 in which the filter 39 is disposed, and a terminal end (the other end) connected to the lower portion of the second ink chamber 32. Yes. The ink in the head liquid chamber 34 passes through the filter 39, flows through the return path 45, and flows into the second ink chamber 32.

  The return path 45 and the supply path 38 constitute a circulation path 80 for circulating ink between the recording head 18 and the ink tank 20.

  In the present embodiment, the return path 45 includes a first return path 47 connected to the head liquid chamber 34 side, a reservoir 49 that temporarily stores ink wider than the first return path 47, and a reservoir 49. And a second return path 51 connected to the second ink chamber 32.

  The reservoir 49 is formed with a film body 53 in which at least a part of the outer wall can be deformed by an external force. The film body 53 is exposed to the outside of the recording head 18 and is disposed at a position where an outer periphery of an eccentric cam 57 described later can contact.

  The first return path 47 is provided with a check valve 61 that allows the ink to flow from the head liquid chamber 34 to the reservoir 49 and prevents the ink from flowing from the reservoir 49 to the head liquid chamber 34. Yes.

  The second return path 51 is provided with a check valve 63 that allows ink to flow from the reservoir 49 to the second ink chamber 32 and prevents ink from flowing from the second ink chamber 32 to the reservoir 49. Has been.

  Note that the check valve 61 and the check valve 63 are not indispensable components, and may be configured without both the check valve 61 and the check valve 63, and either one is provided. Also good.

  The circulation unit 55 arranged on the side of the recording head unit 15 is movable in a direction approaching the recording head unit 15 and a direction separating from the recording head unit 15.

  In the circulation unit 55, as an example of an external force applying unit that applies an external force to the circulation path so that the liquid circulates and deforms at least a part of the circulation path, an eccentricity disposed opposite to the film body 53 is provided. A cam 57 is rotatably provided. The circulation unit 55 is provided with a cap portion 59 for closing the atmosphere opening port 28.

  The eccentric cam 57 is partially different in distance from the rotation center to the outer periphery, and the eccentric cam 57 is in contact with the film body 53 and is not in contact with the film body 53 depending on the rotational position of the eccentric cam 57. Change state to state.

  In a state where the eccentric cam 57 is in contact with the film body 53, the film body 53 is pushed inside the reservoir portion 49 and dented in a concave shape. Further, in a state where the eccentric cam 57 is not in contact with the film body 53, the film body 53 returns to its original state by its elastic force.

  For this reason, the volume of the reservoir 49 changes between the state in which the eccentric cam 57 is in contact with the film body 53 and the state in which the eccentric cam 57 is not in contact with the film body 53. When the volume of the reservoir 49 changes so as to be reduced, the ink is pushed out from the reservoir 49 and flows into the second ink chamber 32 through the check valve 63 that allows the ink to flow.

  When the volume of the reservoir 49 changes from a reduced state to an increase, the ink flows from the head liquid chamber 34 into the reservoir 49 through the check valve 61 that allows ink flow. In this way, a circulation flow is generated by the eccentric cam 57 and the ink circulates in the circulation path 80.

  In addition, if the film body 53 is deformed by the eccentric cam 57, a circulating flow is generated. Therefore, the eccentric cam 57 may be rotated in either direction.

  As described above, in this embodiment, the recording head unit 15 has the circulation path 80, but the drive source for circulating the ink is provided in the circulation unit 55 that is separate from the recording head unit 15.

  Further, the circulation path 80 is entirely provided in the recording head unit 15 and is configured as a continuous flow path in the recording head unit 15. That is, the circulation path 80 does not pass through the outside of the recording head unit 15, and the ink circulates inside the recording head unit 15.

(Operation for circulating ink between the recording head 18 and the ink tank 20)
Next, the operation of circulating ink between the recording head 18 and the ink tank 20 will be described.

  In the inkjet recording apparatus 10 according to the present embodiment, the recording head unit 15 stands by at the stop position when the recording head 18 is not recording. The ink circulation operation is performed on the recording head unit 15 located at the stop position. The timing at which the ink circulation operation is performed is arbitrarily set. For example, after the image recording by the recording head unit 15 is completed, the ink circulation operation is performed when the recording head unit 15 returns to the stop position. .

  In the ink circulation operation according to the present embodiment, first, the circulation unit 55 approaches the recording head unit 15 located at the stop position, and the eccentric cam 57 circulates to a position where it can contact the film body 53 of the reservoir 49. The unit 55 moves.

  Next, the eccentric cam 57 is rotated, and the film body 53 is pushed and dented on the outer periphery of the eccentric cam 57. As a result, the ink in the reservoir 49 is pushed out and flows into the second ink chamber 32 through the check valve 63 that allows the ink to flow.

  Further, when the eccentric cam 57 is rotated and the outer periphery of the eccentric cam 57 is not in contact with the film body 53, the film body 53 returns to its original shape. As a result, the ink flows from the head liquid chamber 34 into the reservoir 49 through the check valve 61 that allows the ink to flow.

  By continuously performing this operation, a circulation flow in which the ink circulates in the circulation path 80 is generated, and the ink circulates between the recording head 18 and the ink tank 20.

  At this time, the circulating ink circulates in the recording head unit 15 without passing through the outside of the recording head unit 15. As a result, the circulation path 80 is not lengthened and has a simple configuration.

  In the present embodiment, the eccentric cam 57 is brought into contact with the film body 53 of the reservoir 49 in the return path 45 to generate a circulation flow on the return path 45 side, but the circulation is generated on the supply path 38 side. The structure which produces a flow may be sufficient. As this configuration, for example, the reservoir portion 49 may be formed in the supply passage 38, and the eccentric cam 57 may be brought into contact with the film body 53 of the reservoir portion 49 to generate a circulation flow on the supply passage 38 side.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made.

(Configuration of recording head unit and circulation unit according to modification)
First, configurations of a recording head unit and a circulation unit according to a modification will be described. FIG. 5 is a schematic diagram illustrating the configuration of a recording head unit and a circulation unit according to a modification. Note that the same parts as those of the recording head unit 15 and the circulation unit 55 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 5, the recording head unit 115 according to the modification includes a return path 145 for returning ink from the head liquid chamber 34 to the second ink chamber 32 instead of the return path 45. The return path 145 has a start end (one end) connected to the outlet 34B of the head liquid chamber 34 in which the filter 39 is disposed, and a terminal end (the other end) connected to the lower portion of the second ink chamber 32. ing. The ink in the head liquid chamber 34 passes through the filter 39, flows through the return path 145, and flows into the second ink chamber 32.

  The return path 145 is configured by an ink flow path having no reservoir 49 and having a constant path width. The return path 145 and the supply path 38 constitute a circulation path 180 according to a modification. Note that the width of the return path 145 may not be constant, and may be partially different.

  In addition, the return path 145 is configured by an elastically deformable flow pipe such as a rubber tube. A deforming portion 145A in which a tube pump 157 described later contacts the outer wall and deforms is formed in an intermediate portion of the return path 145.

  On the upstream side of the deforming portion 145A of the return path 145 in which the tube pump 157 is disposed, ink is allowed to flow from the head liquid chamber 34 to the deforming portion 145A, and ink from the deforming portion 145A to the head liquid chamber 34 is allowed. A check valve 161 for preventing the flow of the gas is disposed.

  On the downstream side of the deforming portion 145A of the return path 145 where the tube pump 157 is disposed, the ink is allowed to flow from the deforming portion 145A to the second ink chamber 32, and from the second ink chamber 32 to the deforming portion 145A. A check valve 163 is disposed to block the ink flow.

  Note that the check valve 161 and the check valve 163 are not indispensable configurations, and may be configured without both the check valve 161 and the check valve 163, or one of them may be provided. Also good.

  The circulation unit 155 according to the modified example is movable in a direction approaching the recording head unit 115 and a direction separating from the recording head unit 115.

  In the circulation unit 155, a tube pump 157 is rotatably provided in place of the eccentric cam 57. The tube pump 157 includes a plurality of rollers 157A that are in contact with the deforming portion 145A of the return path 145. In this tube pump 157, the deformed portion 145A is crushed by the roller 157A and rotated while the deformed portion 145A is crushed by the roller 157A, and the ink inside the return path 145 is pushed downstream. After the roller 157A moves, the crushed portion returns to its original shape by the restoring force of the return path 145. At that time, the inside of the return path 145 is evacuated and the ink on the upstream side is sucked. When the tube pump 157 performs this operation continuously, a circulating flow in which the ink circulates in the circulation path 180 is generated.

  Thus, in this modification, the print head unit 115 has the circulation path 180, but the drive source for circulating the ink is provided in the circulation unit 155 that is separate from the print head unit 115.

  The circulation path 180 is entirely provided in the recording head unit 115 and is configured as a continuous flow path in the recording head unit 115.

  In the present modification, the tube pump 157 arranged on the return path 145 side generates a circulation flow on the return path 45 side, but the structure generates a circulation flow on the supply path 38 side. Also good. As this configuration, for example, the tube pump 157 may be arranged on the supply path 38 side to generate a circulation flow on the supply path 38 side.

(Configuration of recording head unit and circulation unit according to reference example)
Next, configurations of the recording head unit and the circulation unit according to the reference example will be described. FIG. 6 is a schematic diagram illustrating a configuration of a recording head unit and a circulation unit according to a reference example. Note that the same parts as those of the recording head unit 15 and the circulation unit 55 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the recording head unit 215 according to the reference example is replaced with a return path 45, and a first return that forms part of a flow path for returning ink from the head liquid chamber 34 to the second ink chamber 32. A path 247 and a second return path 251 forming a part of a flow path for returning ink from the head liquid chamber 34 to the second ink chamber 32 are provided.

  The first return path 247 has a start end (one end) connected to the outlet 34B of the head liquid chamber 34 in which the filter 39 is disposed, and a terminal end (the other end) exposed to the outside of the recording head unit 215. Are arranged as follows. A slit valve 244 to which a port 250 described later can be connected is provided at the terminal end of the first return path 247. The slit valve 244 is configured in the same manner as the slit valve 44.

  In the middle part of the first return path 247, the ink is allowed to flow from the head liquid chamber 34 to the end part of the first return path 247, and the ink from the end part of the first return path 247 to the head liquid chamber 34 is allowed. A check valve 261 is disposed to prevent the flow of.

  The ink in the head liquid chamber 34 passes through the filter 39, flows into the first return path 247, and flows to the end portion of the first return path 247.

  The second return path 251 is arranged such that a start end (one end) is exposed to the outside of the recording head unit 215 and a terminal end (the other end) is connected to a lower portion of the second ink chamber 32. A slit valve 246 to which a port 252 described later can be connected is provided at the start end of the second return path 251. The slit valve 246 is configured in the same manner as the slit valve 44.

  An intermediate portion of the second return path 251 allows ink to flow from the start end of the second return path 251 to the second ink chamber 32, and from the second ink chamber 32 to the start end of the second return path 251. A check valve 263 is disposed to block the flow of ink.

  Note that the check valve 261 and the check valve 263 are not indispensable configurations, and may be configured without both the check valve 261 and the check valve 263, or may be provided with either one. Also good.

  The ink flowing from the start end of the second return path 251 flows through the second return path 251 and flows into the second ink chamber 32.

  The circulation unit 255 according to the reference example includes a third return path 253 that forms part of a flow path for returning ink from the head liquid chamber 34 to the second ink chamber 32. A port 250 is provided at one end of the third return path 253, and a port 252 is provided at the other end of the third return path 253. The port 250 and the port 252 are configured in the same manner as the port 50.

  When the port 250 is connected to the slit valve 244 and the port 252 is connected to the slit valve 246, the second ink is discharged from the head liquid chamber 34 by the first return path 247, the second return path 251, and the third return path 253. A flow path for returning ink to the chamber 32 is formed.

  The first return path 247, the second return path 251 and the third return path 253, and the supply path 38 constitute a circulation path 280 according to the reference example.

  Further, the third return path 253 is configured by a flow pipe that can be elastically deformed, such as a rubber tube. The circulation unit 255 according to the reference example includes a tube pump 257 around which a flow pipe constituting the third return path 253 is wound.

  The tube pump 257 includes a plurality of rollers 257 </ b> A that come into contact with the outer wall of the third return path 253. In this tube pump 157, the roller 257A crushes the third return path 253, and the roller 257A rotates in a state where the third return path 253 is crushed, thereby pushing the ink inside the third return path 253 to the downstream side. After the roller 257A moves, the crushed portion returns to its original shape by the restoring force of the third return path 253. At that time, the inside of the third return path 253 is evacuated, and the upstream ink is sucked. When the tube pump 257 continuously performs this operation, a circulation flow in which ink circulates in the circulation path 280 is generated.

  As described above, in the reference example, a part of the circulation path 280 and a drive source for circulating the ink are provided in the circulation unit 55 that is a separate body from the recording head unit 15. The port 250 is connected to the slit valve 244, and the port 252 is connected to the slit valve 246, whereby the circulation path 280 is completed.

FIG. 1 is a schematic diagram illustrating a configuration of an ink jet recording apparatus according to the present embodiment. FIG. 2 is a schematic diagram illustrating the configuration of the recording head unit, the replenishment station, and the circulation unit according to the present embodiment. FIG. 3 is a schematic view showing a state where ink is replenished from the replenishment station to the ink tank. FIG. 4 is a schematic diagram illustrating a state in which ink is circulated between the recording head and the ink tank. FIG. 5 is a schematic diagram illustrating the configuration of a recording head unit and a circulation unit according to a modification. FIG. 6 is a schematic diagram illustrating a configuration of a recording head unit and a circulation unit according to a reference example.

Explanation of symbols

10 Inkjet recording device (droplet ejection device)
15 Recording head unit (Droplet ejection head unit)
16 Carriage (moving body)
18 Recording head (Droplet ejection head)
20 Ink tank (liquid reservoir)
53 Film body 57 Eccentric cam (cam, external force applying means)
80 Circulation path 115 Recording head unit (droplet discharge head unit)
157 Tube pump (external force applying means)
180 circuit

Claims (4)

A moving object,
A droplet discharge head provided on the moving body and discharging droplets while moving integrally with the moving body;
A liquid storage section that is provided in the moving body and stores liquid supplied to the droplet discharge head;
A circulation path provided in the movable body, in which the liquid is circulated between the droplet discharge head and the liquid reservoir, and at least a part thereof is deformable by receiving an external force, and a circulation flow is generated by the deformation; ,
A droplet discharge device comprising:   2. The liquid according to claim 1, further comprising an external force applying unit that is configured separately from the moving body and that deforms at least a part of the circulation path by applying an external force to the circulation path so that the liquid circulates. Drop ejection device. The circulation path is formed of a film body in which at least a part of an outer wall is exposed to the outside of the moving body,
The droplet discharge device according to claim 1, wherein the external force applying unit is a cam whose outer periphery is pressed against the film body. A droplet discharge head that is provided on a moving body and discharges droplets while moving integrally with the moving body;
A liquid storage section that is provided in the moving body and stores liquid supplied to the droplet discharge head;
A circulation path provided in the movable body, in which a liquid is circulated between the droplet discharge head and the liquid storage unit, and at least a part thereof can be deformed by an external force, and a circulation flow is generated by the deformation;
A droplet discharge head unit comprising:

Images